Central Bureau for Astronomical Telegrams
IAUC 6148: N Cir 1995; CH Cyg
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Circular No. 6148
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
Phone 617-495-7244/7440/7444 TWX 710-320-6842 ASTROGRAM CAM
MARSDEN@CFA.HARVARD.EDU or GREEN@CFA.HARVARD.EDU (science)
NOVA CIRCINI 1995
A. Evans, Keele University; and R. V. Yudin, Pulkovo Observatory,
report observations of this nova with the 0.75-m telescope (+
UCT polarimeter) at the South African Astronomical Observatory
during Jan. 31-Feb. 5: "We find a polarization through Johnson V of
3.7 +/- 0.3 percent in p.a. 55 +/- 8 deg (typical errors cited),
with no evidence for variability. These values are broadly similar
to those of field stars, suggesting that the polarization of the
nova is interstellar. These observations imply that the reddening
may be high [E(B-V) > 0.5]."
CH CYGNI
B. R. Espey and G. A. Kriss, Hopkins Ultraviolet Telescope
(HUT) team, Astro-2 Space Shuttle mission; and J. J. Johnson and R.
E. Schulte-Ladbeck, Wisconsin Ultraviolet Photopolarimeter Experiment
(WUPPE) team, report ultraviolet and far-ultraviolet observations
of CH Cyg on Mar. 8.22 UT with both the HUT (range 80.0-180.0
nm, resolution about 0.3 nm) and WUPPE (range 140.0-320.0 nm,
resolution about 1.6 nm), 7 days after the ejection event noted by
Iijima (IAUC 6146). Preliminary results follow: "The ultraviolet
spectrum is generally similar to that seen during previous ejection
events. The strongest emission lines seen are those of C II (133.4
nm), O I] (135.6 nm), Si IV + O IV] (140.0 nm), N IV] (148.6 nm), C
IV (154.9 nm), Ni II (159.6 nm), O III] (166.3 nm), N I (174.2 nm),
N III] (174.8 nm), Si III] (189.3 nm), C III] (190.9 nm), C II]
(232.6 nm), and Mg II (279.8 nm). Lyman-alpha and O I 130.4-nm are
hidden in the geocoronal emission profiles. In addition to these
features seen in previous IUE spectra, HUT has detected emission
from C III at 97.7 nm, O VI at 103.2 and 103.8 nm, N II + He II at
108.5 nm, and C III at 117.6 nm. P-Cyg profiles are in evidence
for the C III 117.6-nm, Si IV 140.0-nm, He II 164.0-nm, and N I
174.2-nm lines, with weaker absorption to the blue of the C IV
154.9-nm line. The typical width of the ultraviolet absorption
profiles is about 2000 km/s, slightly broader than those seen in
the optical observations reported by Iijima (ibid.). Weaker lines
in evidence include the Fe II 'UV191 transitions' at 178.6 and
250.9 nm, which are pumped by Lyman-alpha radiation. No emission
from Si II was detected. The continuum rises to the red, with
evidence for Fe II absorption, from 2 x 10E-13 erg cmE-2 sE-1 AE-1
at 100.0 nm to 1 x 10E-12 erg cmE-2 sE-1 AE-1 at 180.0 nm. After a
dip to about half this value around 235.0 nm, the flux recovers
towards 320.0 nm."
1995 March 11 (6148) Daniel W. E. Green
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